NA/Keyer Interface

What is the best way to interface a Heath uMatic keyer and
the NA LPT CW option to a single transceiver? I am getting
ready for field day. Yes, I am aware of the alt-K option.
But sometimes, it is easier to handstroke a unique response
than to use canned or typed responses. Is it possible to
simply parallel these two CW sources? I will be using a
286-AT driving a TS-450AT, (not mine).
Listen for KE0A, I am the station boss for 40/15 and WARC.
Respond directly or to the reflector for mutual benefit.
Equalization not discussed, personal rating system under
development.
73 de bob - nd1h - grand forks, north dakoty